In the beginning of Jack Finney's short story "Contents of a Dead Man's Pocket," Tom said he opened the window because he felt the room was hot. Yet, he changed his mind about his motive when he heard his wife rummaging in their bedroom closet. As he says to himself, "Hot, no--guilty conscience." In other words, Tom knew he raised the window not because the room was hot but because he felt hot due to feeling guilty.
One reason why Tom felt guilty was because he had just asked his wife to go to the movies by herself even though they had planned to go together and he had wanted to see the film too. However, the main reason why he felt guilty is because, deep down inside, he knew he was putting off his wife in favor of pursuing a project for work he knew would not bring him immediate results.
Tom had told his wife he could not go to the movies with her because he had something he needed to get done for work. Yet, the reality is that he was working on an independent project he could easily postpone. He rejected the idea of postponing the project because he wanted to advance in his career. He had wanted to surprise his boss with the proposal and give him time to think about it over the weekend. But, the reality is that he knows the proposal will not bring him immediate benefit. He knows it won't "bring a raise in pay--not immediately, anyway, or as a direct result." He further knows the proposal "won't bring [him] a promotion," not the proposal alone, at any rate. The whole point of the proposal is that it would bring him notice that would eventually, hopefully, lead to a raise and a promotion.
Hence, it is due to his knowledge that the outcome of his project is uncertain that leads him to feel guilty, which in turn makes him feel hot and feel the need to raise the window. He knows he is replacing the certainty of his relationship with his wife with the uncertain prospect of a raise and promotion through undertaking a project he could easily put off.